#include <iostream>
#include <algorithm>

using namespace std;

struct lqacn
{
	int x;
	int y;
}k[5005];

bool slk(lqacn a, lqacn b)
{
	return a.y < b.y;
}

int main()
{
	int n, s, t, g;
	cin >> n >> s >> t >> g;
	int h = t + g;
	for (int i = 1; i <= n; i++)
	{
		cin >> k[i].x >> k[i].y;
	}
	sort(k + 1, k + n + 1, slk);
	int ans = 0;
	for (int i = 1; i <= n; i++)
	{
		if(s > k[i].y && h > k[i].x) ans++;
	}
	cout << ans;
	return 0;
}